Enflurane blood-gas solubility: Influence of weight and hemoglobin

The blood-gas partition coefficient of enflurane was measured in nine nonobese and eight morbidity obese patients and correlated with weight, body mass index, and blood hemoglobin. The enflurane blood-gas partition coefficient was lower in the obese patients than in nonobese patients (mean ± SEM; 2.03 ± 0.02 versus 1.76 ± 0.03, respectively, p < 0.025). There was a negative correlation between enflurane blood solubility and both body mass index and weight (r = -0.59 and -0.55, respectively, p < 0.01). A positive correlation was found between hemoglobin and the enflurane blood-gas coefficient (r = 0.69, p < 0.01). Equilibrium between inspired and alveolar enflurane concentration should be faster in morbidity obese and anemic patients than in healthy, nonobese patients.